All posts tagged Kemp Technologies

Multiple DirectAccess servers can be deployed in a load-balanced cluster to eliminate single crucial points of failure and to provide scalability for the remote access solution. Load balancing can be enabled using the integrated Windows Network Load Balancing (NLB) or an external physical or virtual load balancer.

NLB Drawbacks and Limitations

NLB is often deployed because it is simple and inexpensive. However, NLB suffers from some serious drawbacks that limit its effectiveness in all but the smallest deployments. For example, NLB uses network broadcasts to communicate cluster heartbeat information. Each node in the cluster sends out a heartbeat message every second, which generates a lot of additional network traffic on the link and reduces performance as more nodes are added. Scalability is limited with NLB too, as only 8 nodes are supported, although the practical limit is 4 nodes. Further, NLB supports only round-robin connection distribution.

Enabling load balancing for DirectAccess deployments is crucial for eliminating single points of failure and ensuring the highest levels of availability for the remote access solution. In addition, enabling load balancing allows DirectAccess administrators to quickly and efficiently add capacity in the event more processing power is required.

DirectAccess includes support for load balancing using integrated Windows Network Load Balancing (NLB) and external load balancers (physical or virtual). External load balancers are the recommended choice as they provide superior throughput, more granular traffic distribution, and greater visibility. External load balancers also more scalable, with support for much larger DirectAccess server clusters, up to 32 nodes. NLB is formally limited to 8 nodes, but because it operates at layer 2 in the OSI model and relies on broadcast heartbeat messages, it is effectively limited to 4 nodes.

The KEMP Technologies LoadMaster load balancer is an excellent choice for load balancing the DirectAccess workload. To learn more about configuring the LoadMaster with DirectAccess, join me for a free live webinar on Tuesday, August 16 at 10:00AM PDT where I’ll discuss DirectAccess load balancing in detail. I will also be sharing valuable tips, tricks, and best practices for load balancing DirectAccess.

Windows 10 clients include full support for all enterprise DirectAccess scalability and redundancy features, including automatic site selection and transparent failover for multisite deployments. However, the native site selection process is limited in functionality and often yields unexpected results.

To provide better client support for multisite DirectAccess, a Global Server Load Balancer (GSLB) solution such as the Kemp Technologies LoadMaster GEO can be deployed. Using the LoadMaster’s GSLB functionality can significantly enhance multisite site selection for Windows 10 clients. In addition, it can be used to enable new scenarios not supported natively such as weighted distribution and active/passive failover.

To learn more about how address the shortcomings of DirectAccess multisite using the Kemp LoadMaster GEO, join me for a live webinar on Thursday, July 14, 2106 at 10:00AM EDT where I’ll discuss the following topics.

How Global Server Load Balancing (GSLB) works

How Windows 10 clients choose an entry point

Understand the limitations of the native site selection process for Windows 10 clients

How to use the Kemp LoadMaster GEO to provide true geographic redundancy

With the recent release of Microsoft’s Windows 10 client operating system, many organizations are now planning their migration to Windows 10 from previous versions. For those organizations looking to maximize their investment in Windows 10, many are considering the deployment of DirectAccess with Windows Server 2012 R2.

DirectAccess and Windows 10 are much better together. Windows 10 includes full support for all of the important enterprise features of DirectAccess in Windows Server 2012 R2, including geographic redundancy, transparent site selection, and IP-HTTPS performance improvements. The Kemp LoadMaster load balancer can be used to extend and enhance the native high availability features of DirectAccess, and it can be used to reduce supporting infrastructure requirements.

To learn more about maximizing your investment in Windows 10 with DirectAccess and the Kemp LoadMaster load balancer, be sure to attend our upcoming webinar on Thursday, October 15 when I’ll discuss in detail and demonstrate the advantages of Windows 10 and the Kemp LoadMaster load balancer.

You can register for the Windows Server 2012 R2 DirectAccess and Kemp Technologies LoadMaster webinar here.

In a previous post I outlined how to configure the F5 BIG-IP Local Traffic Manager (LTM) to serve as the Network Location Server (NLS) for a DirectAccess deployment. Many people then asked if it was possible to do the same with the Kemp Technologies LoadMaster load balancing solution. Until now, it was not. However, beginning with release 7.1-28b it is!

After upgrading your Kemp LoadMaster to version 7.1-28b, open the LoadMaster management console, expand Virtual Services, and then click Add New. Specify a Virtual Address, enter 443 for the Port, optionally provide a descriptive Service Name, select TCP for the Protocol, and then click Add this Virtual Service.

Expand SSL Properties and select Enabled for SSL Acceleration. If you have not yet installed the SSL certificate for the NLS, you will be prompted to use a temporary certificate.

Expand Advanced Properties and select 200 OK from the Error Code drop-down list. Optionally you can enter a description for the service in the Error Message box and click Set Message. This will be displayed if someone opens the NLS web site in a web browser.

At the top of the page click Back. If the SSL certificate for the NLS was not previously installed, add it now by clicking Add New.

Click Import Certificate and provide the certificate file as required. Once the certificate is installed successfully, assign the certificate to the NLS virtual service and click Save Changes.

Once complete, update the DNS record for NLS to point to the IP address assigned to the virtual service running on the LoadMaster.

For more information about the Kemp Technologies LoadMaster load balancer and to download a free fully-functional trial, click here. You can also download a completely free and fully-functional version of the Kemp LoadMaster here.

To learn more about the DirectAccess NLS, please refer to the following posts:

Beginning with Windows Server 2012, DirectAccess includes native support for external load balancers. Where high availability is required (which is most deployments!) the use of an external load balancer (physical or virtual) has many advantages over Windows Network Load Balancing (NLB).

While NLB is easy to configure, it is not without serious drawbacks. NLB relies on network broadcasts, which limits its effectiveness in some environments. In addition, NLB supports only a single load distribution mode, which is round robin. NLB also lacks a convenient monitoring interface.

A dedicated load balancing solution provides more robust load balancing and better, more granular traffic control than NLB. Along with this greater control comes increased traffic visibility, with most solutions providing details and insight in to node health, status, and performance. Many solutions also offer Global Server Load Balancing (GSLB) support, which enhances geographic redundancy and offers improvements when performing automatic site selection in multisite deployments.

Often the barrier to adoption for a dedicated external load balancer is cost. Many of the leading solutions are incredibly powerful and feature-rich, but come with a substantial price tag. The Kemp Technologies LoadMaster Load Balancers solution is an excellent, cost-effective alternative and works quite well providing load balancing support for DirectAccess. And to make things even more interesting, they recently announced a completely FREE version of their commercial load balancing product.

The free LoadMaster does have some restrictions, however. For example, you cannot create high availability clusters of LoadMasters. Also, the free LoadMaster is limited in terms of network throughput (20Mbps) and SSL/TLS transaction per second (50, using 2048 bit keys). There is also a limit on the number of virtual servers you can create (1000). The free LoadMaster must also have access to the Internet as it must be able to call home to validate its license every 30 days. You can find a complete model comparison matrix between the free and commercial Kemp LoadMasters Kemp LoadMaster Comparison Chart.

As the free version of the Kemp LoadMaster does not support clustering, technically you still have a single point of failure. However, it can still deliver a net improvement in stability and uptime, as the LoadMaster is a purpose-built platform that requires much less servicing and maintenance than a typical Windows server.

For detailed information about configuring the Kemp LoadMaster to provide load balancing services for DirectAccess, be sure to download the DirectAccess Deployment Guide for Kemp LoadMaster Load Balancers. And if you end up liking the free Kemp LoadMaster load balancer (and I’m confident you will!) you can always upgrade to the full commercial release at any time.

A few months ago I had the opportunity to work with the folks at KEMP Technologies to document the use of their LoadMaster load balancers for Windows Server 2012 R2 DirectAccess deployments. DirectAccess has several critical single points of failure which can benefit from the use of a load balancer. Typically Windows Network Load Balancing (NLB) is used in these scenarios, but NLB suffers from some serious limitations and lacks essential capabilities required to fully address these requirements. The use of an external third-party load balancer can provide better load distribution and more granular traffic control, while at the same time improving availability with intelligent service health checks.

Working with the LoadMaster was a great experience. Installation was quick and simple, and their web-based management console is intuitive and easy to use. The LoadMaster includes essential features that are required for load balancing DirectAccess servers, and advanced capabilities that can be leveraged to enhance geographic redundancy for multisite deployments.

KEMP offers the widest platform coverage with their solutions, including dedicated hardware appliances, virtual appliances for multiple hypervisors including Hyper-V, cloud-based including Microsoft Azure, as well as bare metal support for installation on your own hardware. You can download a fully functional free trial here.